The red Under Armour skull cap Jaden Gronner wears beneath his football helmet has nothing to do with fashion, and everything to do with hearing. Tucked inconspicuously behind the Cromwell-Wright junior’s left ear is a cochlear implant. Gronner is deaf in his left ear and has minimal hearing in his right — the result, his parents believe, of a nasty brush with scarlet fever when he was 13 months old. The skull cap keeps the device firmly in place and relatively free of moisture during activity. Gronner, 17, received the implant three years ago.

When the implant was switched on, Gronner’s left ear suddenly was exposed to the racket of daily life. It took some getting used to. Initially, sound generated by cochlear implants is discordant. Time and training are required to process and interpret the signals. “The first time it was really weird,” Gronner said during the Cardinals’ practice Tuesday afternoon in Cromwell. “After a couple weeks, I started hearing different sounds.” Gronner’s dad, Cromwell-Wright coach Jeff Gronner, said Jaden could understand words with his left ear a month after activation, a rapid turnabout.

“It was really cool for us because we got to see somebody that didn’t have much hearing at all get a cochlear implant and suddenly be able to hear much better,” Drew Libbon, a junior quarterback and linebacker for the Cardinals, said. “That made it a lot easier for us as a team to be able to communicate with him.” Jaden’s expert lip-reading, sharpened out of necessity, hasn’t hurt, either. Time was, he could “hear” better with his eyes.

On the field, just as he does in the classroom, Jaden utilizes an FM system. Attached to a lanyard around Jeff’s neck is a microphone that carries every one of his directives wirelessly to Jaden’s implant. Life-changing as the cochlear implant has been, two specific situations curtail its usefulness: wind and excess background noise. Two of the most common characteristics of high school football games in Northeastern Minnesota? Wind and excess background noise. The FM system bypasses both, giving Jeff a direct line to Jaden.